The overall goal of this project is to address how disproportionate confinement of racial/ethnic minorities-especially African Americans-affects health disparities in the HIV/AIDS epidemic. African Americans comprise only 13% of the general population, but about 40% of incarcerated youth and adults and 50% of new cases of HIV/AIDS. Yet, large multisite national longitudinal studies of HIV/AIDS focus on high- risk samples such as men who have sex with men (MACS), women infected with HIV and other "at-risk" females (WIHS), and infected women and their infants (WITS). These studies do not include adolescents, do not sample correctional populations, and do not examine the effect of incarceration on HIV/AIDS. Most studies of incarcerated populations are cross-sectional and provide limited information on the effects of incarceration. To continue to address this key omission in the literature, we propose to extend the Northwestern Juvenile Project, a longitudinal study of 1829 juvenile justice youth, enrolled at age 10-18 years (1172 males, 657 females;1005 African Americans, 296 non-Hispanic whites, 524 Hispanics, and 4 "other" race/ethnicity). Currently, the HIV/AIDS component of the project (RO1 DA022953) includes only a subsample (n=743) and 10-, 11-, 12-, and 13-year follow-up interviews. We now propose to (1) study the entire sample (originally 1829, now 1678);(2) conduct 3 additional annual interviews (14-, 15-, and 16-year follow-ups), at which time participants will be aged 26-34 years;(3) collect official records to cross-validate self-reported data (on STI status, arrests, incarceration history, and services received);(4) test the entire sample for HIV infection, chlamydia, and gonorrhea;and (5) administer a new module on incarceration, release, and re-entry. Participants are re-interviewed whether they are re-incarcerated or back in the community. Using data collected in prior phases and the additional interviews, we will examine patterns of drug use, drug use disorder, HIV/AIDS risk and infection from adolescence (ages 10-17 years) to emerging adulthood (ages 18-24 years) and young adulthood (age 25 and older). Our Specific Aims focus on how incarceration, release, and re-entry (e.g., age[s] incarcerated, number of incarcerations, length of incarcerations, amount of time spent in the community between incarcerations) affect the following: (1) drug use behaviors (including the number and types of substances used, frequency of use, and route of administration) and drug use disorders (onset, persistence, desistance, and recurrence);(2) HIV/AIDS sex risk behaviors (including unprotected anal or vaginal receptive sex and trading sex for drugs) and injection-risk behaviors;(3) prevalence and incidence of HIV infection and other STIs;(4) the relationship between patterns of drug use and disorder and HIV/AIDS risk behaviors, especially how risk and protective factors predict, moderate, and mediate these relationships. This study responds to the initiatives of NIDA, NIAAA, and other NIH institutes to reduce health disparities in HIV/AIDS in minority populations.